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Homework Help: Buoyancy (Weight of a barbell underwater)

  1. Jan 14, 2009 #1
    A bodybuilder is holding a 20-kg steel barbell above her head. How much force would she have to exert if the barbell were lifted underwater?

    Fb= Density x Volume x Gravity
    Density= mass/volume

    7860= 20/ V

    V= .00254 m^3
    Fb= 1000 x .00245 x 9.81
    Fb= 24.9174 N
  2. jcsd
  3. Jan 14, 2009 #2

    Doc Al

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    Staff: Mentor

    You've found the buoyant force, which is the force exerted by the water. But what's the force that she has to exert?
  4. Jan 14, 2009 #3
    I've never done this type of problem wouldnt it just be mass*bouancy force 24.917 * 20 kg =498.35N
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